"The thing that I'm most interested in at the moment is the so-called Infinite Energy solution - the possibility of finding new ways of tapping into virtually limitless sources of energy."
- Arthur C. Clarke

The state experienced in free fall; a space traveler's weight is apparently reduced to zero.

In the novel, Verne correctly predicts that the three men traveling in a projectile to the moon would experience a weightless state. Being a formidable writer, he does a great job of describing it!

Barbicane clearly explained the consequences to his traveling companions, which greatly interested them. But how should they know when the projectile had reached this neutral point situated at that distance, especially when neither themselves, nor the objects enclosed in the projectile, would be any longer subject to the laws of weight?
Up to this time, the travelers, while admitting that this action was constantly decreasing, had not yet become sensible to its total absence.

But that day, about eleven o'clock in the morning, Nicholl
having accidentally let a glass slip from his hand, the glass, instead of falling, remained suspended in the air.

"Ah!" exclaimed Michel Ardan, "that is rather an amusing piece of natural philosophy."

And immediately divers other objects, firearms and bottles,
abandoned to themselves, held themselves up as by enchantment.
Diana too, placed in space by Michel, reproduced, but without any trick, the wonderful suspension practiced by Caston and Robert Houdin. Indeed the dog did not seem to know that she was floating in air.

The three adventurous companions were surprised and stupefied, despite their scientific reasonings. They felt themselves being carried into the domain of wonders! they felt that weight was really wanting to their bodies. If they stretched out their arms, they did not attempt to fall. Their heads shook on their shoulders. Their feet no longer clung to the floor of the projectile. They were like drunken men having no stability in themselves.

Fancy has depicted men without reflection, others without shadow. But here reality, by the neutralizations of attractive forces, produced men in whom nothing had any weight, and who weighed nothing themselves.

Suddenly Michel, taking a spring, left the floor and remained suspended in the air, like Murillo's monk of the _Cusine des Anges_.

The two friends joined him instantly, and all three formed a miraculous "Ascension" in the center of the projectile.

"Is it to be believed? is it probable? is it possible?"
exclaimed Michel; "and yet it is so.

However, Verne wrote that the men would only achieve a state of weightlessness at the point in the journey where the Earth's gravitational pull and the moon's pull canceled each other out. And, as we know, even shuttle astronauts in orbit a mere 250 miles from the Earth experience weightlessness.

Astronauts in orbit are still subject to Earth's gravity; but they (and the space craft) are constantly falling toward the Earth and thus are weightless. More recently, the term microgravity has been used to describe the weightless state in an orbiting spacecraft. Physicists note that orbiting astronauts experience tidal forces because the gravitational force varies infinitesimally over the distance from head to toe (when pointing straight away from the Earth). Also, if the orbit is low enough to encounter even the slightest amount of atmosphere, the drag on the spacecraft will provide a slight deceleration due to friction.

In 1638, The Man in the Moone by Bishop Francis Godwind, was published posthumously. It contains what appears to be the first account of the concept of weightlessness.